Fabric tensioning means for knitting machines



June 21, 1960 F. P. TRUMPIO 2,941,387

FABRIC TENSIONING MEANS FOR KNITTING MACHINES Filed June 4, 1958 3 Sheets-Sheet 1 IN V EN TOR. flan/r R Pam via June 21, 1960 F. P.1'RUMPIO 2,941,387

FABRIC TENSIONING MEANS FOR KNITTING MACHINES Filed June 4, 1958 3 Sheets-Sheet 2 INVENTOR. from? P Pump/o FABRIC TENSIONING MEANS FOR KNITTING MACHINES Filed June 4, 1958 F. P. TRUMPIO June 21, 1960 3 Sheets-Sheet 3 FlE-Ei- E INVENTOR. Fran/r Fun lb 2,941,387 FABRIC TENSIONING MEANS FOR KNITTING MACHINES atent 0,

Frank P. Trumpio, Reading, Pa., assignmto Textile Machine Works, Wyomissing, Pa., a corporation of Pennsylvania Filed June 4, 1958, Ser. No. 739,700

4 Claims. (Cl. 66-147) The present invention relates to warp knitting machines and more particularly to means in such machines for maintaining a fabric of substantially uniform width as it travels along its path from the knitting instrumentalities upon which it was formed to the take-up mechamsm.

AS is well known in warp knitting machines, yarns are fed to the needles by yarn guides which move back and forth between the needles and longitudinally thereof to wrap theyarns around the needles to be formed into courses of loops. Following the formation of a course of loops the guides are idly shifted distances of one or more needles and the yarns formed into loops on the new needles according to the desired pattern of the fabric to be formed. From the needles the fabric is taken up by a take-up roll and then wound upon a fabric roll in the usual manner. Due to the tension built up in the fabric loops, which increases or decreases according to the length of the loops being formed, there is a tendency for the selvages to curl or roll and the fabric to shrink coursewise so that the width of the fabric as it engages the take-up roll is greatly reduced from its width as formed on the knitting instrumentalities. Consequently, while the take-up roll exerts a predetermined normal tension control in the loops across the greater portion of the width of the fabric, the take-up roll has very little if any control on the loops along the selva-ges with the result that the edge portions of the fabric become defective. Another objection to the curling and shrinking in the fabric is that scanning devices, which are employed to detect defects in the fabric, cannot be used across the full'width of the fabric.

It is therefore an object of the invention to provide means in a warp knitting machine for engaging the selvages' of a fabric formed on the machine to maintain the fabric width substantially as formed from the fabricating means to the take-up mechanism of the machine.

Another object of the invention is to provide a means in a warp knitting machine for engaging the selvages of a fabric, which means acts with the take-up means to apply a uniform tension in the loops across substantially the full width of the fabric.

A further object of the invention is to provide a warp knitting machine with means for engaging the selvages of a fabric, which means is driven from the take-up means and acts therewith in applying tension on the fabric across the full Width thereof.

A still further object of the invention is the provision of means to drive the selvage engaging means at variable speeds relatively to the take-up means whereby the tension applied to the edge and center portions of the fabric may be of different amounts.

With these and other objects in view which will become apparent from the following detailed description of the illustrative embodiment of the invention shown in the accompanying drawings, the invention resides in the novel elements, features of construction and cooperation of parts, as hereinafter more out in the claims.

In the drawings:

Figure 1 is a front elevational view of a Warp knitting machine having mechanism according to the instant invention incorporated therein;

Fig. 2 is an enlarged view similar to a portion of the left end of the machine of Fig. 1 showing the take-up mechanism;

Fig. 3 is a view on an enlarged scale taken substantially along the line 3-3 of Fig. 2, parts being shown in elevation and others being shown in cross section;

Fig. 4 is a cross-sectional view on an enlarged scale taken along the line 4-4 of Fig. 1;

Fig. 5 is a view similar to Fig. 2 and enlarged relative thereto with certain parts being omitted to more clearly show further details of the invention.

Fig. 6 is an elevational view taken in the direction of the arrows 6-6 of Fig. 5, parts being shown in cross section;

Fig. 7 is a cross-sectional view on an enlarged scale taken along the line 7-7 of Fig. 4;

Fig. 8 is a top plan view of a portion of the mechanism of Fig. 4 a viewed in the direction of the arrow 8; and i Fig. 9 is a cross-sectional view on an enlarged scale taken along the line 99 of Fig. 4.

Referring to the drawings, and more particularly to Figs. 1 and 4, there is shown a warp knitting machine including a base 10 and end frames 11 which form the framework for sinkers 15, a resser member 16 for closing the beards of the needles, and yarn guides 17 for yarn 20 carried on beams 19. The needles 12, sinkers 15 and presser member 16 are operated by drive means indicated generally at 21 to form the yarns 20, which are lapped around the needles by the yarn guides 17, into loops of a fabric 22. As the fabric 22 is formed, it is drawn from the needles 12 over a support bar 23 by a take-up roll 25 which is provided with a covering of friction material as is usual in such rolls to facilitate the take-up action. The take-up roll 25 is driven in a common manner through gear means indicated diagrammatically at 26 (Figs. 1 and 2) which in turn is operated by change speed means (not shown) from the drive means 21. From the take-up roll 25, the fabric passes over a guide roll 27 to a fabric roll 30 upon which the fabric is wound, the fabric roll being frictionally driven by means (not shown) from the take-up roll.

Due to the inherent elasticity in the fabric loops which is developed during the knitting thereof, there is not only a marked tendency for the fabric edges to roll up but there is also a tendency for the fabric to shrink coursewise thereof as the fabric is advanced along its take-up path between the needles 12 and take-up roll 25. This rolling of the edges and reduction in width of the fabric not only results. in the failure of the take-up roll to maintain a uniform tension inthe loops along the selvages but also limits the effectiveness of scanning devices which are employed to detect fabric faults across the full width of the fabric. In order 'to maintain the fabric at substantially the same width that it is knitted and to maintain a constant take-up tension over the full width of the fabric at least through a substantial portion of its path between the needles 12 and the takeup roll 25, a selvage engaging device 32 is provided at each side of the fabric to engage the fabric edges and advance them in timed relationto the take-up action on the fabric as applied by the take-up roll. The devices extendsubstantially parallel to thecenterline of the fabric and to each other. Only the-left selvage engaging device particularly pointed supporting spring bearded needles 12,

32 is shown and described in detail herein but it is to be understood that the device for engaging the opposite selvage of the fabric is identical in structure except that the parts are made right hand instead of left hand, 7

t The selvage engaging device 32 comprises a seriesof pins 35 which are formed as an integral part of'or are secured to studs 36 as by brazing or the li'ke; The'studs are threadably'carried in flanges37 which extend atright angles from side links 38 at one side of a roller'type chain 40 (Figs. 8 and 9), The chain 40 is mounted on a sprocket 41 which acts as a driver for advancing'the chain in the fabric take-up direction, as hereinafter set forth, and idler sprockets 42 and 43 (Fig. 4); Each of the idler sprockets isrotatably mounted on a stud 45- be tween a shouldered portion 46 of the stud 'and'a collar 47 secured on the stud (Figs. 4 and 8); Thestuds 45 extend through and are secured in fixed position on a plate 50, with the shouldered portions 46 bearing against one" side face of the plate, by nuts 51-. A guide'plate'52 which isadjustably mounted on the plate between the sprockets 41 and 42 by screws 53 is adapted to engage between the side links of the chain to'prevent lateralmovement of the chain from its normal path of movement in the take-up direction (Fig. 7). The plate 50 is secured by bolts 55 to a bracket 56 carried in fixed position on one end of a stub shaft 57 (Figs. 5 and '6') which is supported in fixed position in a bracket 60 securedto the left end frame 11 by studs 61. Thesprocket '41 is secured to one end of a shaft 62 which is supported for rotative movement in the plate 50 and bracket 60. The shaft 62'isheld against axial movement by collars 65 which are secured on the shaft in engagement with facing surfaces of the plate 50and bracket 60 (Fig. 5). The shaft 62 is also supported at a point intermediate its ends by a bracket 66 which is secured to a fixed part 67 of the machine (Figs. 2, 3, and 5).

In order to compensate for a variation in the tension in the fabric loops, which is caused primarily by a'variation in the length of loops as determined by the so-called quality of the fabric, the shaft 62, sprocket 41 and chain 40 are adapted to be driven at different speeds from the take-up roll 25 to thereby vary the take-up movement of the selvages of the fabric in such relation to the center of the fabric as to maintain a substantially uniform tension in the loops acro'ss the full width of the fabric. For so driving the shaft 62 and chain 40 the shaft carries a series of three sprockets 70, 71 and 72 which are of different; diameters and which are axially movable along the shaft for selective engagement with the lower run of a chain 75. Each of the sprockets 70, 71 and 72 is provided with a set screw 76 for securing it to the shaft when in engagement with the chain 75. The chain is mounted on and driven by a sprocket 77 which is fixed on the take-up'roll 25 at one side of the shaft 62- and the lower run of the chain is maintained in engagement with the selected sprocket 70, 71 or 72 by an idler sprocket 80 at the other side of the shaft 62. The sprocket 80 is r0- tatably mounted on a stud 81, which'is carried in an arm 82 mounted in fixed adjusted position on the stub shaft 57 (Figs. 3 and 5).

In order to insure engagement of the edge of the-fabric 22 with the pins 35, the fabric, as it is drawn in the take-up direction from the needles 12, is guided beneath abase portion 85 of a U-shaped member 86 for engagement witha leg portion 87 thereof; The leg-portion 87 overlies the fabric inwardly of the pins 35 and acts to press the fabric onto the pins as the chain- 40 is advancedin the take-up direction. The U-shaped member '86 is supported in fixed position by a second leg 90 thereof which is held between -a pair of washers91- carried on the stud 45 for the sprocket 43 betweenthe plate 50 and the nut 51 (Fig. 8). Preferably at a pointadjacent to the take-up roll 25 and before the fabric engages the take-up roll, the fabric is forced off of the PlHS'BS'bY a" curved finger 92 of a stripping member 95 Ijhestripping 4 member 95 is secured in adjusted position on the plate 50 by screws 96 with the highest part of the curved finger lying above the outer ends of the pins 35. Under certain conditions, however, it may be desirable to strip the fabric from the pins 35 at a point closer to the sprocket 43. For this purpose each selvage .may be guided over a finger 100 which is carried ori'plate 50 adjacent to the idler sprocket 42 as indicated in Fig; 4.

It will be obvious from the foregoing that the selvage engaging device of the instant invention acts to maintain the width of the fabric substantially the same as knitted through a substantial'portion of its path or movement between the needles and the take-up roll. The engaging device also acts to advance the edge portions of the fabric in such timed relation to the take-up movement of the center portion of the fabric as to maintain a substantially uniform tension in the fabric loops across the full width of the fabric.

It will be understood that the improvements specifically shown and described by whichthe above results"areobtained canb'e changed and modified in" various was without departing from the" invention disclosed and hereinafter claimed.

I claim:

1. In a warp knitting machine having knitting means, means for feeding yarns to said knitting means to be formed into selvaged fabric thereby, and-means for tak ing up said fabric as it is formed, in combination with' means for engaging the selvages of said fabric between said knitting means and said take-up means to" maintain said selvages parallel to each other'and the fabric at -substantially the same width as formed by said knitting means, and means for driving saidengaging means from said take-up means, said driving means including means to vary the speed of said engaging means in relation to the speed of said take-up means.

2. In a warp knitting machine-having knitting means,- means for feeding yarns to said knitting means to b'e formed into selvaged fabric thereby, and means for taking up said fabric as it is formed, in combination with means for engaging the selvages of said fabric to' maintain-said selvages parallel to each other and the fabric at substantially the same width as formed by said knitting means, and means for driving said selvage engaging means from said take-up means and at diflierentspeeds relatively thereto;

3. In a warpknitting machine having knitting means for forming flat selvaged fabric and means for takingupsaid fabric as it is formed, in combination with means for engaging each selvage of'the fabric between said knitting means and take-up 'means to maintainsa'id selvages parallel to each other and the fabric at sub'-' stantially the same width as formed by said knitting means, including an endless chain; means for mountingsaid chain for movement along a path parallel to the fabric take-up direction, pins carried on said chain, means adjacent to said knitting means for engaging a selvage of said fabric on said pins, mearis' adjacent to said take-up means for disengaging said selvage from said pins, means for driving said chain fromsaid takeup means, and means for varying the speed of said driving means in relation" to the speed of said take-up along a path between said knitting means and-take-up means and parallel to the fabric'take-up'directiompins" on said'chain, means adjacent'to said knitting meansfor' n aging a'selvage of saidfabric'on said=pins, meansad'-" jacent to said take-up means for disengaging said selvage from said pins, a driving connection between said take-up means and said chain, and means for varying the speed of said driving connection in relation to the speed of said take-up means.

References Cited in the file of this patent UNITED STATES PATENTS 2,070,147 Thompson Feb. 9, 1937 6 Hawley et a1. Jan. 6, 1948 Trumpio Aug. 28, 1956 Lambach et a1 Oct. 29, 1957 FOREIGN PATENTS Germany June 20, 1942 France May 22, 1945 

